Switching to Photopolymer from Magnesium

Hi all,

I’ve just made the investment in the boxcar base and have printed my first project using photopolymer. It turned out pretty good but overall the impressions were not as crisp and even as I would of liked (see attachment). I have some ideas on how I can fix the issues I had, but would like some feedback on what others think.

First off, crisp impression. The photopolymer overall just didn’t seem as forgiving as magnesium. I guess it just seemed to “spread” more, especially on the text. To remedy this I tried to raise my roller height and add more ink but then the ink seemed to not want to adhere to the plate evenly.

Second, the counters in my text on the photopolymer plate seemed to be really sallow, thus ink filled the counters which made for bad impressions. I tried the roller height/ more ink again. This helped some what.

And last, soft packing or hard packing? I always used soft with magnesium and this seemed to workout well. With the photopolymer this seem to added to the “spread”.

I really like the convenience of photopolymer so any advice on how to get better results would be very appreciated!

FYI: I’m printing on a 7 x 11” Improved Pearl with deep relief photopolymer.

image: projectsample.jpg


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A close up

image: IMG_2758.JPG



This is getting to be somewhat of a constant refrain and quite disheartening. Photopolymer plates are capable of the finest letterpress printing. Hands down. It is disheartening to hear otherwise from folks who refuse to use the right tools for the job.

I hate to say this but do your homework. Wrong press. Wrong base. Wrong plates. Wrong economics. Wrong theory.


You say you’re using deep relief plates — on deep relief base? This is the combination recommended by Boxcar for this kind of press and if it’s wrong then their recommendation must be wrong. I don’t know the depth of etch of deep relief photopolymer — it may not be as deep as standard magnesium (someone posted on here recently that all photopolymer is etched to the same depth - true?). If you are seeking the deep impression look for your work photopolymer may not be the proper medium for you. It may have to do with the shallower angle of the beard or shoulder.

On the other hand you should be able to ink just the face if your rollers are correctly set so ink in the counters shouldn’t be a problem. Go back and look at earlier posts about roller-vs-truck diameter, roller height, etc. You may need to reset everything from scratch.

Gerald, would you please clarify what you mean by “wrong press” (and “wrong economics”)?

I haven’t tried photopolymer outside of a class, but I do have a Pearl No. 11 and just might try it, someday…so this may be news I can use.



Thank you for your comment. Yes, it appears that I am using the same press that Boxcar uses in their instructional videos so I must be headed in the right direction. And yes, deep relief base with deep relief plates—their recommendation. I’m thinking it has something to do with the rollers so I’m going to head down that path and look at those posts.

Thanks again.


I own your book so apparently I’ve done my homework (or maybe not). I’m not going to run out and buy a flatbed so I’ll just have to work with what I have.

My guess would be that the press is over-inked and/or the rollers are set too low and inking onto the side of the relief as well as the face. You might want to ink up the press, pull off the chase and have a look the way the plate is inked.

Daniel Morris
The Arm Letterpress
Brooklyn, NY


As I mentioned this is a problem that continues to show up on this list, and not so much on other letterpress lists; I assume because the majority of folks posting here are rather new entries to the field. Most of the solutions proffered seem to revolve around the mechanics of this type of press, specifically, rollers and and trucks. And this seems to make sense, except that the problem seems not to exist with photomechanical engravings or type.

Okay, that might be a clue. On the PPLetterpress list a while back this came up and it was mentioned that this problem does not show up on Patmags with thick steel-backed plates. This has been my observation as well. I have clients who use these dinosaurs and they have no issues.

The Patmag is not a “convenient” base, the plates need adhesive to keep them from being pushed around by the rollers, you DO need a line gauge for registration, and they have a significant variance in tolerance and are not parallelized. But, they do use a more stable floor structure, the plates made for them have a hardness rating that is compatible with letterpress, and the magnetized rubber covering gives with impression. This could very well be the reason they work on smaller platens and C&Ps and the like. Perhaps, heresy, but, maybe not.

Other considerations with your specific problem are that you are simply pushing the impression beyond what makes sense with the inking. Inking and impression are related. This is a technical issue, not an aesthetic one (more heresy). Plus, in order to get adequate ink coverage on your larger blocks of type it seems you are over inking your smaller type. These should be printed separately so that you can control the inking. Not very convenient, but likely the way it is. Even more heresy.

You mention your counters filling. Yes they will with improper inking and impression. Photopolymer plates configured for letterpress, no matter what their thickness. have a limited “relative reverse relief depth.” That would be your counters. Doesn’t matter if your plate is thick or thin. You can’t force them to be anything other than what they are.

Do photopolymer plates splay under heavy impression? of course they do. They are plastic with resilient qualities. That actually makes them, along with their tack, an ideal printing surface, as long as you work within the expected parameters.


I love a good debate! And….. one again I’ve got to agree and disagree with my esteemed colleagues who love PP plates.

PP plates are indeed capable of carrying a fine image. If you just look at some of the books that Gerald and others have done, you will be convinced. I don’t agree however that you are using the wrong tools. There is no reason you shouldn’t be able to get a nice crisp impression using PP plates on your Golding….. IF you set it up and use it correctly.

As far as the discussion about bases goes, I won’t comment. We use wood, not Boxcar or Honeycomb bases…. so I have no idea if the one you have is the right one or not. Wood works fine in my shop, but this must be one of those cases where magic is involved since most of the current Gurus claim it doesn’t work. ;) ( I just had to toss that one in… no offense to the Gurus intended!)

But back to the topic at hand: Since PP plates are a bit softer than metal plates, your packing, impression, and roller set-up needs to be adjusted accordingly. I’ve found that if my pressure is too high, or my packing too soft, the image will suffer the problems you are describing. Hard packing seems to work best for me. PP plates are not the best for impressing into the paper, though. For that, metal plates are better.

I concur that you are asking a lot of the press’ inking system by printing both large and small areas in one pass. The problem is that if you have enough ink to cover the larger area, then you are over-inking the small type. This is more of an inking / impression problem than a plate problem, and even your metal plate jobs will look better if you take a two-pass approach.

I don’t agree that….. ” Photopolymer plates are capable of the finest letterpress printing. Hands down…..” While it is a good, or perhaps even excellent system, it is not the “finest” letterpress process out there….. especially for tiny details, small type or deep impressions. (actually we are discussing relief printing, not “letterpress” since there is no movable type involved) For this, engraved, etched, or roll mastered metal plates are vastly superior, especially engraved steel plates. This is what my business does. We use the process primarily because the printed image quality cannot be matched with PP or etched magnesium plates, and thus the finished products are very difficult to copy / pirate / counterfeit. (Even finer work can be done on Itaglio presses with metal plates…. but that would not be considered “letterpress” or relief printing.)

Of course such work requires a bit more technical expertise, and is considerably more expensive…. and thus beyond the needs of most shops. BUT it is not as difficult as old curmudgeons such as myself would lead you to believe, no is there any magic to it. It’s just another process. If I learned how to do it, you could too.

Finally, I tend to feel the same way about folks asking the same technical questions over and over again. (Not you nschwaab, but in general.) If newbies would take the time to read through the archives here at Briar Press, they’d find a wealth of information to answer 99% of the questions they ask. Sooo… my advice to newbies would be to take the time to read and study….. and THEN begin printing. It would save them a lot of work and paper.


Hi winking

This is off the thread path. Regarding wood bases.

I note that Heidelberg, in one of its manuals, suggests not to use engravings with wood bases. Problem is density issues. More of a problem with photopolymer plates, especially polyester-backed, as photopolymer responds not only to matters of the printing surface, i.e., makeready, inking, roller pressure, substrate, etc., but to what is underneath it as well. The Princess and the Pea. Which is why aluminum is usually the base of choice.

At any rate, I was once commissioned to reproduce several hundred 19th century wood engravings from various children’s illustrated books (have I told this before? of course, I have). Some good stuff, except for the condition of the engravings. Lots of nightmarish makeready. One thing, some advice from Gaylord Schanilec, was that you could actually effect a portion of the engraving by putting a small piece of underlay directly under where the problem was located on the block. In other words, you could use the pressure of the press to force the wood grain to respond and effect the surface. It actually did work as he suggested.

Wood is very pliable, even when it is a hundred and fifty years old, actually even when it is four hundred and fifty years old, which is another story:

At any rate, all of which is why I would suspect its use as a reliable precision base support for photopolymer plates.


“I just had to toss that one in… no offense to the Gurus intended”

I assume this was directed in part to me. No problem, Dave, I am finally resigned, after many years of it, to no longer post anywhere, anytime, unless I am obliged to (my own lists).

It’s been good going back and forth with you though here. Just a bit tired of the pointlessness of it all.

All best.



1. People with experience and expertise will not get frustrated and quit posting here. It isn’t pointless at all, from my perspective; it has been extremely helpful over the year I have been on this site. It’s the closest many of us will ever get to having a mentor. Books and classes are helpful too, of course, but they just can’t cover every eventuality that arises in this detail-packed, technicality-riddled pursuit.

I can see how answering the same questions over and over could get pretty irksome, though, so …

2. New people will at least search the archives here before posting their questions, not asking for other people’s time until they (we) have invested some of their (our) own.

3. Summer, not the predicted slushstorm, will arrive in Minnesota this afternoon so I can take my horse out on the trail. (OT, yes, but I needed another wish to fill out the mandatory three-wish quota.)

Gerald …. not all wood is created equal, you know. If one uses the wrong kind, without expertise, it can be difficult to achieve good results. It’s a skill, just like anything else.

As far as the Guru comment goes, it was not aimed at you at all. The biggest problem I see nowadays is a large crop of inexperience folks giving “experienced advice” to new printers…. things like using Crisco to clean your rollers, or bizarre forms of packing, or “you can’t do that on your press…” or any one of a hundred bits of bogus advice we’ve both seen floating around lately. My comment was aimed at those folks who put forth such rubbish without having the experience to really know what they are saying.

SO… you can’t quit posting now. If you do, the Gurus win. (and I won’t have anyone to debate!)


I guess I owe you a response; God, I am so weak in my resolve, or maybe it’s just so late and I am so tired from the day’s work or something. Or maybe I’m just full of crap.

You earlier directly asked about wrong press and wrong economics and I did not respond. I’m not sure that you can expect certain levels of printing quality from this type of press or minimum investment in equipment, tools, supplies, etc. There is only a certain level that you can achieve. I don’t mean to denigrate the work performed here but think that, to some extent, given the materials at hand, that’s about all you can hope for.

I doubt this will satisfy the inquiry, but, quite frankly, those are my thoughts. I’m not trying to be a snob about this.

BTW, I spent six years in Mpls/St Paul (1980-86) and have very fond memories of those years. They were very productive years for me. I had a shop in the Rossmor Building in St Paul and later in Inkunabula Arts (Campbell-Logan Bindery) in Minneapolis.

Cheers, and best of luck in your printing.


Hi there,
I have had my share of bad results when using wood as base for my plates. So I realized that and went on looking for the good stuff, metal.
Assuming that you are exposing the negative correctly, with proper vacuum and clean class and no dust around, in a clean enviroment; the plate is then developed in a correct posture, no curls and absolutely straight; your brushes are clean and so is the developer machine, and everything is properly leveled. The press is set correctly and leveled, rollers are good; the plate is absolutely the height and the ink is properly worked out and has good viscosity; the trucks are clean with no oils and the packing is the proper one. If you do it as the above steps you should have a better result.
You can implement a step by step procedure and follow it. When you take a short cut, down the line you pay for it.

I would start finding some metal base and try to see if it improves, as well as checking all else.
Good luck.


Wow, there has really been some good “debate” since my last visit.
Thanks again to everybody for their comments. My latest project turned out fantastic. First of all, the design was much more consistent in terms of printing areas. Next, I took all of the tape off the rails and started from scratch — building up the tape until the inking was correct. Now that the rollers are set correctly I’m not having the counter inking problem. I used lettra and press board as my packing material (I saw that on another thread).

It has been interesting to see how different the setup needed to be from mag. to photopolymer to achieve a good result. Really, it was only my intention to see if there was someone else out there that had already traveled down this same road. It was not my intention to make anyone repeat themselves.